Process and device for producing hollow blocks for manufacturing seamless tubes



May 15, 1923.

, BECKER PROCESS AND DEVICE FOR PRODUCING HOLLOW BLOCKS FOR MANUFACTURING SEAMLESS TUBES Filed Jan. 5O 1923 ANN] Patented May l5, 11923.

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THEODOR BECKER, OF DUSSELDOBF, GERM.

PROCESS AND DEVICE FOR PRODUCING HOLLOWBLOCKS FOR MANUFACTURING SEAM- LESS TUBES.

Application filed January 30, 1923. Serial No. 615,907.

' T all whom it may concern:

Be-it known that I, THEonoR BECKER, a citizen of Germany, residing at Dusseldorf, Germany, have invented certain new and useful lmpprovements in Processes and Devices for roducing Hollow Blocks for Manufacturing Seamless Tubes, of which the following is a specification.

This invention relates to a process and apparatus for producing hollow metal blooms for manufacturing seamless tubes, and more particularly to a process of this kind in which a piercing device of the Mannesniann type is used for producing the hole in the hot metal block or ingot. It is known that the rod to which the mandrel is fixed and over which the work piece is rolled, is not withdrawn after the piercing operation, but that the hollowed bodyafter it has been forced over the mandrel, is drawn off the mandrel rod in the direction of its axis. To permit this operation the pivoted mandrel rod holder is swung aside So as to enable the hollowed body to pass.

The usual practice in piercing round metal castings or the like up to the present time consists in allowing such castings to become cold and then reheating them to the temperature required for producing the hol-- low bodies. It has, however, proved to be advantageous to carry out the piercing operation in a cross-rolling mill according to my pending patent a plication Ser. No. 496,833 of the 30th of ugust, 1921, before the cast metal block or ingot has cooled down. To this end the block or ingot after it is cast, is immediately placed in a suitable furnace where it is kept hot and the involved heat equalised for successfully piercing in Mannesmann cross-rolling machines or the like. When, as in the old process, the block or ingot-casting is allowed to cool down and is subsequently reheated before the piercing operation is performed the interior metal structure contains rents and crevices which are more or less oxidized. The twisting stress of any cross-rolling causes such crevices to open to such an extent as to tear and in many cases render the produced 'hollow body useless. These stresses being particularly heavy when metal blocks or ingots of large dimensions are to be treated, by reheating the work-piece it is difiicult to heat the core up to the same temperature as the metal envelope or outer portion of the casting: the welding of the oxidized centre crevices are therefore most difficult and complicated. It, on the other hand, the piercing operation is carried out in a cross-rolling mill or press without previous cooling and reheating of the metal block or ingot the core of the latter will still be of a pasty consistency and before the critical state of the interior metal is reached, the outside pressure due to cross-rolling, or the resistance of mould or receiver in the metal press solidifies the interior of the ingot or metal block while passing over the piercing mandrel and mandrel rod. A difiiculty however which arises in the process with the Mannesmann piercer is the necessity for an effective cooling of the piercing mandrel and mandrel rod, particularly if the piercing operations are to be carried out in quick succession.

In accordance with this invention this effective cooling is secured by conducting cooling water into the interior of the hollow mandrel rod through the interior of the mandrel rod holder when the latter is in position for operation, while the cooling water is cut off when the mandrel rod holder is swung out of its operating position.

A constructional form of a device for carryingv out the invention is shown in the annexed drawing.

The drawing shows a round metal block, partly in longitudinal section, passing through a pair of cross rollers, and a longitudinal section through the piercing mandrel and the hollow mandrel rod together with its cooling water-pipe, the mandrel rod being held at its other end by the mandrel rod holder shown partly in section and partly in elevation. The other parts of the device are omitted to simplify the illustration.

Referring to the drawing, 0 is a round metal block, P and Q two tapered rollers inclined towards each other and journalled and driven as in tube producing mills of the Mannesmann type. H is the piercing mandrel over which the metal block or ingotis rolled between the two tapered rollers which rotate the block while forcing it over the mandrel H. The piercing mandrel is fixed to one end of a hollow mandrel rod I through which cooling water is admitted and conducted out again through an annular channel between the hollow mandrel rod I and a pipe .K inserted in the mandrel rod. The cooling .ner. A is the mandrel rod holder which can 'be swung round a pivot L attached to the support M. The mandrel rod holder is shown in position for operationcand it can be swung out sideways of this position through an angle of about 90 so as to enable the hollowed metal operated upon to be drawn over the mandrel rod, and past the mandrel .rod holder when the hollowed work piece or tube is removed ,from the. mill.

\Vhen the mandrel rod holder A is in its operative or closed position it is locked by a detent-D pivoted on the supportM with its free end engaging a notch in'the mandrel rod holder and pressed thereagainst by a spring Nof sufficient power tohold the detent in locked engagement with said mandrel rod holder against the pressure of a spring E of less power on a'push-rod for closing the water inlet cock when the mandrel rod holder is shifted into an inoperative position. When the' mandrel rod holder is to be opened or swung aside so as to al low the hollowed bloom to pass, the detent D is swung back against an abutment or motion limiting surface D*. In accordance with the invention the mandrel rod socket C receives the end of the mandrel rod remote from the mandrel, and said end is firmly clamped in said socket by suitable tool holding means of known construction when the mandrel rod holder is in its operative position and released when desired to swing the mandrel rod holder into an inoperative position; said socket and the socket adjuster C on the mandrel rod holder being provided with a hole or bore C and a cooling water pipe B provided with a cock B is arranged so that one end of the pipe leads into the said bore 0, while the other end thereof is connected, as by a hose coupling or the like, to a cooling water feed pipe (not shown). The handle or lever of the cock B is linked to a thrust rod F which carries a plate F at its other end. A guide support Gris attached to the mandrel rod holder and; carries a guide-plate g having a hole therein through which the thrust rod F passes, said plate being arranged to receive the thrust of a spring E, associated with the said guide. In the o erative position shown in the drawing t e thrust rod F is pushed up by the detent D against the action of the spring E and the water cock B is maintained open so that the cooling water flows out from the pipe B through the bore G into the internal pipe K in the hollow mandrel rod and, after cooling the mandrel H,- flows back through the ann'ular passage between I'and K and then out at the rlght hand end of the rod I. By this drelirod are continually kept cool during the operation. After this operation the detent D is released and swung back against the abutment D and the spring E then pulls down the rod F was to automatically close the cock B and stop the water flowing into the mandrel rod I. The-mandrel rod holder may now be swung aside so as to enable the tube or hollowed metal block to be pulled over the mandrel rod I and out of the mill.

\Vhen the mandrel rod holder A is reclosed for a new operation the water'cock ls reopened so that, when a new metal block or ingot is introduced between the tapered rollers, the mandrel and the mandrel rod are cooled. during the time of the operation.

The constructional form of the device illustrated in the drawing is particularly advantageous but, if desired, the automatic opening and closing of the water cock can be dispensed with. In this case the cock B must be closed by hand before the detent D is released, and the cock must be opened again when the mandrel rod holder is closed and the detentD is restored to its locking position. The illustrated construction is only an example and many diversions can be made without departing from the scope of the invention, the essential feature of which is the process of introducing the cooling water forhollow mandrel rods in piercing mills of the kind described through the interior of the mandrel rod holder.

The metal block 0 is passed into the piercing mill straight from the steel foundry after the heat is sufliciently equalized, or straight from a furnace into which it is brought for the purpose of equalization of the heat whereby the core is kept at a weld ing temperature until introduced into the mill. If the mandrel and mandrel rod were not effectively cooled by the cooling process, which is only interrupted at short intervals during which the mandrel rod holder' is swung aside as to allow the hollow metal block to pass,cthe high temperatureof the interior of the round metal block would be liable not only to quickly destroy the mandrel, but to cause 1t to weld together with the piercing mandrel.

I claim:

1. The herein described process of'producin hollow metal bodies, which donsists in ro ling a hot metal block or ingot over a piercing mandrel carried by a hollow man1 drel rod having the end thereof remote from the mandrel secured in a fixed position, causing the passage of water through said hollow rod to the interior of the mandrel and thence out, during the rolling and piercing operation, then stopping the flow, of water and releasing the fixed end of the mandrel rod and moving thefixing means into position to permit the hollow body to. be. drawn off the mandrel rod in the direction of its axis. 1

2. The herein described process of producing hollow metal bodies, which consists in rolling a metal casting as it is taken from the mold and before it has cooled down over a mandrel at one end of a hollow mandrel rod having the other end secured in a fixed position, causing the passage of water to the interior of the mandrel and thence out, during the rolling and piercing operation, then stopping the flow of water and moving the mandrel rod securing means toward one side of the mandrel rod so as to permit the metal casting to be drawn off the mandrel rod in the direction of its axis.

3. The herein described process of forming hollow metal bodies, which consists in supporting a hollow mandrel carrying rod with one end in a fixed position in communication with a source of Water supply and a mandrel on the other end thereof in position to pierce the metal body, rolling a hot metal body over said mandrel so as to cause thepassage of the mandrel through said body, introducing water through the hollow mandrel rod during the piercing operation, then stopping the flow of water and releasing the fixed end of the mandrel'rod and moving the fixing means out of the plane of the mandrel rod so as to permit the hollow body to be drawn oil' the mandrel rod in the direction of its axis.

4. A metal piercing. device comprising tapered rollers for rolling and advancing hot metal, a mandrel adapted to pass through the core of the metal, a hollow mandrel rod for holding the said mandrel, a pipe in the mandrel rod, a pivoted mandrel rod holder or thrust with a passage that leads into the said pipe, means for closing the said passage when the mandrel rod holder is swung round the said pivot into its inoperative position, and means for opening the said passage when the mandrel rod holder is in its operative position.

5. A metal piercing device comprising tapered rollers for rolling and advancing hot metal, a mandrel adapted to pass through the core of the metal, a hollow mandrel rod for holding the said mandrel, a pipe in the mandrel rod, a pivoted mandrel rod holder or thrust with a passage that leads into the said pipe, a cock connected with the said pipe, a spring for closing the said cock when the mandrel rod holder is swung round the said pivot into its inoperative position, and means for opening the cock when the holder or thrust is in its operative position.

-6. A metal piercing device comprising tapered rollers for rolling and advancing hot metal, a mandrel adapted to pass through the core of the metal, a hollow mandrel rod for holding the said mandrel, a pipe in the mandrel rod, a pivoted mandrel rod holder with a passage that leads into the said pipe, a cock in the said pipe,

a spring for closing the said cock when the mandrel rod holder is swung round the said pivot into its inoperative position, a detent for locking the mandrel rod holder in its operative position, and a member adapted to be moved against the action of the said spring by the said detent and to open the said cock when the mandrel rod holder is moved into its operative position.

7. A device for producing hollow metal bodies, said device comprising means for rolling and advancing a hot metal body, a mandrel for piercing said body as it advances, a hollow mandrel rod for holding said mandrel in operative position, a pipe in said mandrel rod, the adjacent ends of said pipe and said hollow rod being in communication with the interior of said mandrel, means for holdng the end of said mandrel rod remote from said mandrel in a fixed position, a water passage leading from said holding means into said pipe and out through said mandrel rod around said pipe, said holding means being adapted to be swung into an inoperative position out of the plane of said mandrel rod, means for closing said passage when said device is swung into inoperative position, and means for opening said passage when said device is moved into its operative position.

In testimony whereof I afiix my signature in presence of two witnesses.

THEODOR BECKER.

Witnesses:

PAUL TUDEN, FRAU HUBERT TUDEN. 

